Ken Pole's most recent article on the subject is not accurate. He should have researched the subject more thoroughly before hitting the send button.
The fact is that Sikorsky originally proposed to Canada a MH-92 with the CT7-8A engine at an estimated aircraft mission weight (unknown at the time because the MH-92 was just a paper aircraft) that was about 3000 lbs lighter than the aircraft eventually came in at (its currently estimated to be 29,400 lbs MGTOW).
The FAA Type Certificate Data Sheet for the CT7 FAA TCDS #E8NE (available on the FAA website) confirms that the dry weights of the CT7-8A and the CT7-8A1 are identical. In GE's defence, the Cyclone engine is therefore NOT heavier than anticipated. The difference between the CT7-8A and the CT7-8A1 is related to their different engine fuel filters and slightly different power output ... not their weight.
The same TCDS also confirms that the recently certified (21 May 2012) CT7-8A7 engine (same dry weight as the CT7-8A! BTW) failed to meet the required 10% take-off and OEI power increase needed for the Cyclone to meet the contract OEI performance requirements.
I attach a comparison below... you have to read the data presented against the initial order of column titles at the top of the list because the PPrune site can't seem to accept the table as extracted.. it may still be understandable as presented but to get a clearer picture of the data presented, go to the FAA's online TCDS Library and ask for TCDS E8NE.
Extract from FAA Type Certificate Data Sheet E8NE Revision 27
CT7-8A1
CT7-8A7
SHP Increase
% Increase
Maximum Continous
2041 (CT7-8A1)
2323 (CT7-8A7)
282 SHP increase
13.8% increase
Take Off ~ 5 Minute
2538 (CT7-8A1)
2685 (CT7-8A7)
147 SHP increase
5.8% increase
30 Minute
2334 (CT7-8A1)
2627 (CT7-8A7)
293 SHP increase
12.6% increase
OEI ~ Continuous
2495 (CT7-8A1)
2627 (CT7-8A7)
132 SHP increase
5.3% increase
OEI ~ 2 Minute
2502 (CT7-8A1)
2667 (CT7-8A7)
165 SHP increase
6.6% increase
OEI ~ 30 Second
2712 (CT7-8A1)
2788 (CT7-8A7)
76 SHP increase
2.8% increase
NOTE 45. The Instructions for Continued Airworthiness (ICA) for the CT7-8A6/-8A7 engines are incomplete. No aircraft with these engines will be eligible for a Standard Airworthiness Certificate until the ICA are complete and accepted.
The Cyclone's underpower issue is still unresolved.